Traditional printing devices rely on a mechanically operated carriage to transport a print head in a linear direction as other mechanics advance a print medium in an orthogonal direction. As the print head moves over the print medium an image may be laid down. Portable printers have been developed through technologies that reduce the size of the operating mechanics. However, the principles of providing relative movement between the print head and print medium remain the same as traditional printing devices. Accordingly, these mechanics limit the reduction of size of the printer as well as the material that may be used as the print medium.
Handheld printing devices have been developed that ostensibly allow an operator to manipulate a handheld device over a print medium in order to print an image onto the medium. However, these devices are challenged by the unpredictable and nonlinear movement of the device by the operator. The variations of operator movement, including rotation and tilt of the device itself, make it difficult to determine the precise location of the print head relative to the print surface of the print medium. This type of positioning error may have deleterious effects of the quality of the printed image.
Moreover, with conventional handheld printing devices it is assumed that the print medium will have a flat or planar print surface on which to perform the printing operation. However, if the print medium has a print surface that includes portions that include curved, bumpy, sharp edges, or have other types of surface irregularities that result in the print surface being non-planar, then it may be very difficult, if not impossible, to successfully print an image onto such a surface using conventional techniques and devices. That is, attempts to print on a non-planar print surface using conventional techniques and devices may result in a degraded image being printed onto the print surface or the printing ink being misdirected and ending up being deposited at unwanted locations such as on the user.